White fields in summer: it's salt

REDFIELD - As you drive across areas of northeastern South Dakota, you might notice large, irregular white spots developing in fields and pastures. These spots are the result of salt accumulation at the soil surface. Several factors contribute to the development of saline soils, but a high water table is a prime cause of the problem. Leaching of salts over time has created saline groundwater in the area. The water carrying the salts will seek the lower areas of the field due to gravity. It will then rise to the surface near the low spots due to capillary rise. In capillary rise, water moves from where the soil is saturated to drier soil against the force of gravity, like a sponge set on a puddle of water. Evaporation then dries the soil and pulls water, by capillary flow, from the wet soil zone. Because only pure water evaporates, salts are left behind. Soil areas that are severely affected by salts often have a bright white, crusty appearance when dry. However, there may be areas that produce poorly, but there are no visible signs of a problem. The extent of the problem can only be identified with a soil test. One can be obtained at the SDSU Soils Testing Lab at Brookings. Once the results are determined by testing, management decisions can be made to help combat the problem. Producers can then select the right crop and variety for the situation. Tolerant grasses to consider include tall and crested wheatgrass, wild rye, saltgrass, alkaligrass, barley and ryegrass. Barley, sugar beets, triticale and wheat are the most salt tolerant grain and field crops in South Dakota. No-till or reduced minimum tillage systems that use shallow tillage are recommended for seedbed preparation in saline soils. Salts leached away by winter snowmelt and spring rains can be returned to the surface by deep spring tillage. Seeding when the salt levels are the lowest provides the best chance to successfully establish a crop. This is typically after snowmelt or spring rains. Use a long-season, deep-rooted crop to control the water table depth. Finally, drainage is a great ally in the fight against saline spots. Low permeability layers restrict the flow of water “out of the bottom” much slower than evapotranspiration removes water “out the top.” Improving natural drainage or installing artificial drainage can help with the movement of water. Any artificial drainage installed needs to be done according to county, district, or state drainage laws. For more information on the management of saline salts, contact your local Extension office or the Water Resource Institute at SDSU at 605-688-4910. Keep 'em Laughing Where do frogs change? In a croak room! Wear your repellent It is the middle of summer and the weather offers a lot of chance to do outdoor activities. However, you will want to provide protection for your family and friends from those pesky mosquitoes that are waiting for you. Personal repellents offer the best protection against mosquitoes that can transmit West Nile Virus and other diseases. Any product containing picaridin, DEET, IR3535, or oil of lemon eucalyptus will give personal protection. Always use any repellents according to the label, and avoid applying them to infants under 2 months of age. In addition you can increase your protection by wearing loose-fitting, long-sleeved clothing and by not being outside when mosquitoes are most active. For more information on repellents and mosquito control, contact your local Extension office or go online at http://sdces.sdstate.edu/westnile/publications.htm. Coming events: July 21-23 Ð State 4-H Horse Show, State Fairgrounds, Huron July 24 Ð State 4-H Livestock Judging Contest, State Fairgrounds, Huron